1. Field of the Invention
The present invention relates to a gear, a method and a device for manufacturing a gear, wherein the gear is formed on a forging process by a die having an inner peripheral surface, on which a plurality of top surface corresponding to a bottom surface of the gear and both projected side surfaces corresponding to tooth surfaces thereof and sandwiching the top surface, wherein the plurality of top surface and the both projected side surfaces of the die connect smoothly each others and wherein the tooth surfaces and the bottom surface of the formed gear connect to each other smoothly. The formed gear has the property of high intensity at a tooth root thereof and wide effective area of tooth form.
2. Related Art
In a conventional method for manufacturing a gear, as shown in FIG. 15, a primary material was formed by hot forging and a surface of the formed material was shaped on a lathe. Then, a gear is cut on the surface thereof by a gear hobbing machine and the cut gear is finished by shaving, or the gear is finished by gear grinding machine or honing machine after heat treating the cut gear.